1. Field of the Invention
This invention relates to a rugged, low cost fluid flow meter having an optional fiber sensing element that is adapted to provide an accurate (digital) representation of the rate (e.g. velocity, volume, and mass) of fluid flow in a remote or inaccessible channel.
2. Prior Art
There presently exists the need to be able to accurately and non-electrically measure the rate of flow of a fluid in a channel, which channel may be remotely located from or inaccessible to a control or test station and which fluid may be characterized as volatile or hazardous, if exposed to a spark. By way of example, an accurate indication of certain physical parameters, such as, velocity, mass, and volume, of a fluid (e.g. liquid oxygen, hydrozene, or gasoline) flowing in a relatively narrow or remotely located channel is necessary in order to efficiently control the operation of certain fluid systems, such as a fuel management system, a chemical processing system, and the like.
However, conventional mechanical flow meters are typically either cumbersome in size and weight or relatively expensive to fabricate, so as to be unsuitable for measuring the rate of fluid flow in a remote or narrow channel. When optical techniques have been employed in the past to provide an indication of fluid flow, some of either couplers, analog-to-digital conversion apparatus, or optical-to-electric or electric-to-optical interfaces have been undesirably required, whereby the reliability, flexibility, and overall cost of the system may be adversely affected. Moreover, in the event that an accurate digital representation of the rate of fluid flow is desired, conventional flowmeters are not easily adapted to provide such a representation without the utilization of relatively complex circuitry.
Examples of conventional sensing apparatus which include optical techniques to provide an indication of a physical parameter of a fluid can be found in the following U.S. patents:
______________________________________ U.S. Pat. No. Issue Date ______________________________________ 2,892,378 June 30, 1959 3,163,767 December 29, 1964 3,273,447 September 20, 1966 3,807,390 April 30, 1974 ______________________________________